对于具有重复键的行，如何获得最长记录？

Question

给定下表，缺少任何唯一键，如何按ID分组并获得最长的Permissions列？

SampleTable：

id | Permissions
------------------------------------
1  | Walk, Swim
1  | Walk, Sit, Swim, Run, Jump, Lay
1  | !Walk, Sit, Lay
2  | Walk, Sit, Swim
3  | !Walk, Sit, Swim
3  | Walk, Sit, Swim

我试过了：

SELECT r.id, r.Permissions
FROM SampleTable AS r
CROSS APPLY (
    SELECT TOP 1 u.id, u.Permissions
    FROM SampleTable AS u
    GROUP BY u.id, u.Permissions
    HAVING u.id = r.id
    ORDER BY MAX(LEN(Permissions)) DESC
) AS u

但是我没有得到正确的结果。

我正在寻找类似的结果：

id | Permissions
-----------------------------------
1 | Walk, Sit, Swim, Run, Jump, Lay
2 | Walk, Sit, Swim
3 | !Walk, Sit, Swim

编辑：
这已经被回答，谢谢。但顺便说一句，我应该将我的SQL设置为：

SELECT r.id, u.Permissions
FROM SampleTable AS r
CROSS APPLY (
    SELECT TOP 1 u.id, u.Permissions
    FROM SampleTable AS u
    WHERE u.id = r.id
    ORDER BY LEN(Permissions) DESC
) AS u
GROUP BY r.id, u.Permissions

Answer 1

您可以使用row_number（）over（）。如：

with cte as (
    Select id, Permissions
    row_number() over( partition by id order by LEN(Permissions) desc) as rnum
    from SampleTable
) Select id, Permissions from cte where rnum = 1